Investigation on influencing factors of wheel polygonization of a plateau high-speed EMU train

Purpose–This study aims to investigate the cause of high-order wheel polygonization in a plateau high-speed electric multiple unit(EMU)train.Design/methodology/approach–A series of field tests were conducted to measure the vibration accelerations of the axle box and bogie when the wheels of the EMU train passed through tracks with normal rail roughness after re-profiling.Additionally,the dynamic characteristics of the track,wheelset and bogie were also measured.These measurements provided insights into the mechanisms that lead to wheel polygonization.Findings–The results of the field tests indicate that wheel polygonal wear in theEMUtrain primarily exhibits 14–16 and 25–27 harmonic orders.The passing frequencies of wheel polygonization were approximately 283–323 Hz and 505–545 Hz,which closely match the dominated frequencies of axle box and bogie vibrations.These findings suggest that the fixed-frequency vibrations originate from the natural modes of the wheelset and bogie,which can be excited by wheel/rail irregularities.Originality/value–The study provides novel insights into the mechanisms of high-order wheel polygonization in plateau high-speed EMU trains.Futher,the results indicate that operating the EMU train on mixed lines at variable speeds could potentially mitigate high-order polygonal wear,providing practical value for improving the safety,performance and maintenance efficiency of high-speed EMU trains.

JR East aims for driverless Shinkansen operation

East Japan Railway Company(JR East)is aiming to“realize driverless train operation”as one of the key measures to respond to rapid changes in the business environment.Currently,Automatic Train Operation(ATO)equipment is not installed on the Shinkansen,but there are plans to introduce ATO or driverless operation in the near future.From 2018-2021,the Ministry of Land,Infrastructure,Transport and Tourism(MLIT)held the“ATO Technology Study Group for Railways”in which the concept of technical requirements necessary for driverless operation was discussed.In 2021,JR East conducted the GOA4 demonstration test on the Joetsu Shinkansen.In this test,we were able to confirm the basic functions of Shinkansen vehicles such as automatic departure control,speed control,fixed position stop control,and remote stop control using ATO.We aim to realize unattended operation(GOA4)for deadhead trains between Niigata Station and the Niigata Shinkansen Rolling Stock Center by the end of the 2020 s,and driverless operation(GOA3)for passenger trains of the Joetsu Shinkansen by the mid-2030s and continue to develop the necessary technologies and build systems.

Current status and prospects of research on safety situation awareness of high speed railway operation environment

Purpose–The safety of high-speed rail operation environments is an important guarantee for the safe operation of high-speed rail.The operating environment of the high-speed rail is complex,and the main factors affecting the safety of high-speed rail operating environment include meteorological disasters,perimeter intrusion and external environmental hazards.The purpose of the paper is to elaborate on the current research status and team research progress on the perception of safety situation in high-speed rail operation environment and to propose directions for further research in the future.Design/methodology/approach–In terms of the mechanism and spatio-temporal evolution law of the main influencing factors on the safety of high-speed rail operation environments,the research status is elaborated,and the latest research progress and achievements of the team are introduced.This paper elaborates on the research status and introduces the latest research progress and achievements of the team in terms of meteorological,perimeter and external environmental situation perception methods for high-speed rail operation.Findings–Based on the technical route of“situational awareness evaluation warning active control,”a technical system for monitoring the safety of high-speed train operation environments has been formed.Relevant theoretical and technical research and application have been carried out around the impact of meteorological disasters,perimeter intrusion and the external environment on high-speed rail safety.These works strongly support the improvement of China’s railway environmental safety guarantee technology.Originality/value–With the operation of CR450 high-speed trains with a speed of 400 kmper hour and the application of high-speed train autonomous driving technology in the future,new and higher requirements have been put forward for the safety of high-speed rail operation environments.The following five aspects of work are urgently needed:(1)Research the single factor disaster mechanism of wind,rain,snow,lightning,etc.for high-speed railways with a speed of 400 kms per hour,and based on this,study the evolution characteristics of multiple safety factors and the correlation between the high-speed driving safety environment,revealing the coupling disastermechanism ofmultiple influencing factors;(2)Research covers multi-source data fusion methods and associated features such as disaster monitoring data,meteorological information,route characteristics and terrain and landforms,studying the spatio-temporal evolution laws of meteorological disasters,perimeter intrusions and external environmental hazards;(3)In terms of meteorological disaster situation awareness,research high-precision prediction methods for meteorological information time series along high-speed rail lines and study the realization of small-scale real-time dynamic and accurate prediction of meteorological disasters along high-speed rail lines;(4)In terms of perimeter intrusion,research amulti-modal fusion perception method for typical scenarios of high-speed rail operation in all time,all weather and all coverage and combine artificial intelligence technology to achieve comprehensive and accurate perception of perimeter security risks along the high-speed rail line and(5)In terms of external environment,based on the existing general network framework for change detection,we will carry out research on change detection and algorithms in the surrounding environment of highspeed rail.

High-Speed Trains Automatic Operation with Protection Constraints: A Resilient Nonlinear Gain-based Feedback Control Approach

This paper addresses the control design for automatic train operation of high-speed trains with protection constraints.A new resilient nonlinear gain-based feedback control approach is proposed,which is capable of guaranteeing,under some proper non-restrictive initial conditions,the protection constraints control raised by the distance-to-go(moving authority)curve and automatic train protection in practice.A new hyperbolic tangent function-based model is presented to mimic the whole operation process of high-speed trains.The proposed feedback control methods are easily implementable and computationally inexpensive because the presence of only two feedback gains guarantee satisfactory tracking performance and closed-loop stability,no adaptations of unknown parameters,function approximation of unknown nonlinearities,and attenuation of external disturbances in the proposed control strategies.Finally,rigorous proofs and comparative simulation results are given to demonstrate the effectiveness of the proposed approaches.

Operational Safety Assessment of a High-Speed Train Exposed to the Strong Gust Wind

The operational safety characteristics of trains exposed to a strong wind have caused great concern in recent years.In the present paper,the effect of the strong gust wind on a high-speed train is investigated.A typical gust wind model for any wind angle,named“Chinese hat gust wind model”,was first constructed,and an algorithm for computing the aerodynamic loads was elaborated accordingly.A vehicle system dynamic model was then set up in order to investigate the vehicle system dynamic characteristics.The assessment of the operational safety has been conducted by means of characteristic wind curves(CWC).As some of the parameters of the wind-train system were difficult to measure,we also investigated the impact of the uncertain system parameters on the CWC.Results indicate that,the descending order of the operational safety index of the vehicle for each wind angle is 90°-60°-120°-30°-150°,and the worst condition for the operational safety occurs when the wind angle reaches around 90°.According to our findings,the gust factor and aerodynamic side force coefficient have great impact on the critical wind speed.Thus,these two parameters require special attention when considering the operational safety of a railway vehicle subjected to strong gust wind.

Xi’an-Chengdu High-Speed Railway Starts Operation

High-speed trains linking Xihn, capital of Northwest Chinas Shaanxi Province, and southwestern metropolis Chengdu, capital of Sichuan Province, began operation on December 6, 2017.

A train timetable rescheduling approach based on multi-train tracking optimization of high-speed railways

Purpose–This paper aims to propose a train timetable rescheduling(TTR)approach from the perspective of multi-train tracking optimization based on the mutual spatiotemporal information in the high-speed railway signaling system.Design/methodology/approach–Firstly,a single-train trajectory optimization(STTO)model is constructed based on train dynamics and operating conditions.The train kinematics parameters,including acceleration,speed and time at each position,are calculated to predict the arrival times in the train timetable.A STTO algorithm is developed to optimize a single-train time-efficient driving strategy.Then,a TTR approach based on multi-train tracking optimization(TTR-MTTO)is proposed with mutual information.The constraints of temporary speed restriction(TSR)and end of authority are decoupled to calculate the tracking trajectory of the backward tracking train.The multi-train trajectories at each position are optimized to generate a timeefficient train timetable.Findings–The numerical experiment is performed on the Beijing-Tianjin high-speed railway line and CR400AF.The STTO algorithm predicts the train’s planned arrival time to calculate the total train delay(TTD).As for the TSR scenario,the proposed TTR-MTTO can reduce TTD by 60.60%compared with the traditional TTR approach with dispatchers’experience.Moreover,TTR-MTTO can optimize a time-efficient train timetable to help dispatchers reschedule trains more reasonably.Originality/value–With the cooperative relationship and mutual information between train rescheduling and control,the proposed TTR-MTTO approach can automatically generate a time-efficient train timetable to reduce the total train delay and the work intensity of dispatchers.

Progress in high-speed train technology around the world

This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum operating speed. Emphasis is given to the newly developed high-speed train in China, CRH380. The theoretical foundations and future development of CRH380 are briefly discussed.

Running safety and seismic optimization of a fault-crossing simply-supported girder bridge for high-speed railways based on a train-track-bridge coupling system

Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on ABAQUS.The rationality of the established model was thoroughly discussed.The horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently performed.The safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)indicators.Parameter optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction coefficient.Results of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare earthquakes.In addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,respectively.The speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track irregularity.The running safety of the train was improved by increasing the fastener stiffness and isolation layer friction coefficient.At the rail fastener lateral stiffness of 60 kN/mm and isolation layer friction coefficients of 0.9 and 0.8,respectively,the safe running speed limits of the high-speed train increased to 250 km/h and 100 km/h under frequent and design earthquakes,respectively.

Optimization of maintenance strategy for high-speed railwaycatenary system based on multistate model

A multi-objective optimization model considering both reliability and maintenance cost is proposed to solve the contradiction between reliability and maintenance cost in high-speed railway catenary system maintenance activities.The non-dominated sorting genetic algorithm 2(NSGA2)is applied to multi-objective optimization,and the optimization result is a set of Pareto solutions.Firstly,multistate failure mode analysis is conducted for the main devices leading to the failure of catenary,and then the reliability and failure mode of the whole catenary system is analyzed.The mathematical relationship between system reliability and maintenance cost is derived considering the existing catenary preventive maintenance mode to improve the reliability of the system.Secondly,an improved NSGA2(INSGA2)is proposed,which strengths population diversity by improving selection operator,and introduces local search strategy to ensure that population distribution is more uniform.The comparison results of the two algorithms before and after improvement on the zero-ductility transition(ZDT)series functions show that the population diversity is better and the solution is more uniform using INSGA2.Finally,the INSGA2 is applied to multi-objective optimization of system reliability and maintenance cost in different maintenance periods.The decision-makers can choose the reasonable solutions as the maintenance plans in the optimization results by weighing the relationship between the system reliability and the maintenance cost.The selected maintenance plans can ensure the lowest maintenance cost while the system reliability is as high as possible.

A Genetic Based Fuzzy Q-Learning Flow Controller for High-Speed Networks

For the congestion problems in high-speed networks, a genetic based fuzzy Q-learning flow controller is proposed. Because of the uncertainties and highly time-varying, it is not easy to accurately obtain the complete information for high-speed networks. In this case, the Q-learning, which is independent of mathematic model, and prior-knowledge, has good performance. The fuzzy inference is introduced in order to facilitate generalization in large state space, and the genetic operators are used to obtain the consequent parts of fuzzy rules. Simulation results show that the proposed controller can learn to take the best action to regulate source flow with the features of high throughput and low packet loss ratio, and can avoid the occurrence of congestion effectively.

Delay recovery model for high-speed trains with compressed train dwell time and running time

Modeling the application of train operation adjustment actions to recover from delays is of great importance to supporting the decision-making of dispatchers.In this study,the effects of two train operation adjustment actions on train delay recovery were explored using train operation records from scheduled and actual train timetables.First,the modeling data were sorted to extract the possible influencing factors under two typical train operation adjustment actions,namely the compression of the train dwell time at stations and the compression of the train running time in sections.Stepwise regression methods were then employed to determine the importance of the influencing factors corresponding to the train delay recovery time,namely the delay time,the scheduled supplement time,the running interval,the occurrence time,and the place where the delay occurred,under the two train operation adjustment actions.Finally,the gradient-boosted regression tree(GBRT)algorithm was applied to construct a delay recovery model to predict the delay recovery effects of the train operation adjustment actions.A comparison of the prediction results of the GBRT model with those of a random forest model confirmed the better performance of the GBRT prediction model.

Evaluation and optimization analysis of high-speed rail network structure in Northeast China under the background of northeast revitalization

The construction of high-speed rail(HSR)network has promoted the social-economic ties of cities,accelerated the compression of time and space,and changed the pattern of regional development.In this paper,with the adoption of the operation frequency data of HSR from 12306 website,and based on the HSR connection strength model and social network analysis model,as well as according to the HSR connection strength,HSR network density,centrality,agglomeration subgroup,and other indicators,we analyzed the characteristics of HSR network structure in Northeast China.Results show that the number of HSR cities in Northeast China is small,cities in HSR network generally exhibit weak connectivity,and the existence of HSR network marginalizes cities such as Ulanhot,Baicheng,and Songyuan,which significantly reduce the overall network connectivity of Northeast China.The overall centrality of HSR network in Northeast China is characterized by“one axis,four edges”;specifically,the one axis is located in Harbin-Dalian transportation line and the four edges are located on both sides of the main axis of Harbin-Dalian transportation line.Eight agglomeration subgroups(four double city subgroups and four multi city subgroups)have formed in Northeast China.The core status of Shenyang in HSR network is improved significantly,and“one axis and two wings”HSR network in Liaoning Province is improved significantly.With the gradual expansion of Chaoyang-Fuxin,Dandong-Benxi,and Jilin-Yanji branch networks,the“point axis”HSR network mode in Northeast China has gradually developed and matured.In the future,it is recommended to rely on eight agglomerating subgroups to encrypt HSR network structure,create secondary node central cities,and gradually build a new pattern of opening up in Northeast China.

Statistical delay distribution analysis on high-speed railway trains

The focus of this study is to explore the statis-tical distribution models of high-speed railway (HSR) train delays. Based on actual HSR operational data, the delay causes and their classification, delay frequency, number of affected trains, and space–time delay distributions are discussed. Eleven types of delay events are classified, and a detailed analysis of delay distribution for each classifica-tion is presented. Models of delay probability delay prob-ability distribution for each cause are proposed. Different distribution functions, including the lognormal, exponen-tial, gamma, uniform, logistic, and normal distribution, were selected to estimate and model delay patterns. The most appropriate distribution, which can approximate the delay duration corresponding to each cause, is derived. Subsequently, the Kolmogorov–Smirnov (K–S) test was used to test the goodness of fit of different train delay distribution models and the associated parameter values. The test results show that the distribution of the test data is consistent with that of the selected models. The fitting distribution models show the execution effect of the timetable and help in finding out the potential conflicts in real-time train operations.

Assessment and Analysis of Carrying Capacity of 350 km/h EMUs Operating on Beijing-Shanghai Highspeed Railway

This paper makes an analysis of the impact on the structure of the corridortype train working diagram by increasing the 350 km/h train pairs of Beijing-Shanghai High-speed Railway(HSR).According to the requirements of operation speed diversity,the multi-station receiving characteristics of cross-line trains and different train stopping schemes,this paper proposes a scheme of adding 350 km/h train pairs via computer analysis of carrying capability mode.The scheme is divided into three stages:(1)Initial stage:It is planned to increase trains running at 350 km/h,with 15~26 pairs of trains put into operation;(2)Rapid increase stage:27~142 pairs of 350 km/h trains are put into operation;(3)Full replacement stage:143~195 pairs of 350 km/h trains are put into operation,during which the number of cross-line trains under operation is controlled,the number of cross-line trains in each section is determined,the operation and connection scheme of cross-line trains is adjusted and the train stopping scheme is optimized.The results of this study were used for the adjustment of the train working diagram in the third quarter of June 25,2021 to increase the number of 350 km/h train pairs from 19 to 30 on Beijing-Shanghai HSR.350 km/h trains are evenly arranged during 7:00—19:00 on the train working diagram and 300 km/h trains are arranged by making full use of every time and space,to improve the travelling speed on Beijing-Shanghai HSR as a whole.

基于三维结构的列车车体操作主断过电压仿真分析与试验研究

目前,对列车过电压的研究可分为现场试验研究与电路仿真研究。电路仿真研究着重关注过电压幅值分布情况,操作主断过电压的振荡频率也是其重要特性,在研究其抑制方法时需要同时考虑过电压的幅值大小与频率特性,而目前对过电压的频率分布研究较少,为操作主断过电压抑制研究提供指导,以车体、高压电缆及钢轨等部件的三维结构为基础,提出一种新的列车操作主断过电压仿真模型。通过该模型,仿真了列车操作主断路器时高压电缆芯线及各车体的暂态过电压特性,得到各车车体过电压的分布情况,仿真结果表明,1车车体操作过电幅值最大达6.10 kV,4车最小,1~4车过电压幅值均在1 kV以上,并发现车体操作主断过电压的主要振荡频率有两个:0.70 MHz及1.30 MHz。进一步通过现车静态试验验证列车操作主断过电压的分布特性及频谱特性的准确性,试验数据表明仿真结果在过电压幅值分布上极为准确,幅值大小除4车外仿真与试验误差不超过5%,频谱特性方面仿真与试验均有2个主要振荡频率,可认为仿真与试验具有一致性。因此认为基于三维结构的仿真模型具备高精度的仿真能力,能模拟出操作过电压的特性并为过电压抑制研究提供指导。

基于多向差分进化算法的氢燃料电池市域动车组运行协同优化

为提高氢燃料电池市域动车组的运行经济性,该文提出一种基于多向差分进化算法的氢燃料电池市域动车组运行协同优化方法。针对氢燃料电池市域动车组运行速度曲线与能量管理的耦合影响,以日均损耗价值成本评价运行综合经济性,通过多向差分进化算法离线优化运行速度和能量管理规则,并根据离线优化结果,对燃料电池和锂电池进行实时功率分配。最后,基于硬件在环平台验证所提方法在单运行区间和多运行区间下的有效性。结果表明,所提方法能够有效降低氢燃料电池市域动车组的日均损耗价值,并保证收敛精度和维持锂电池荷电状态。而且在单运行区间下,所提方法的日均损耗价值分别比优化前、仅速度优化、仅能量管理优化方法降低了15.21%、6.9%、9.51%;在多运行区间下,所提方法的日均价值损耗比分步优化方法降低了5.07%。

考虑动车组接续的区域城际网运行图加线模型

加线是运行图调图阶段常用的技术,加线时若能协同考虑动车组周转接续对降低动车组运用成本、提高行车组织效率具有重要意义。以区域城际高速铁路网络化运营为背景,以对既有运行图调整幅度最小化、动车组周转接续数量最大化为目标,考虑行车安全、接发车能力、动车组周转接续等约束,构建考虑动车组周转接续的多线路运行图协同加线优化模型;基于ε约束法处理多目标优化问题,设计滚动时域算法以提高模型求解效率。最后,选取宁杭高速铁路、沪昆高速铁路、京沪高速铁路组成的区域城际网进行案例分析,结果表明所构建方法能够实现运行图加线与车底运用的协同优化,相比既有单线加线模式,动车组平均利用率提高9.7%。该研究能够为运行图调整提供方法支持,提高调图质量与效率。

调度集中系统发送无线进路预告的改进方案

调度集中系统中存在重复车次时,无线进路预告可能被发送到错误车次,对司机造成困扰。为此提出一种在GSM-R网络覆盖区段对调度集中系统发送无线进路预告的改进方案。该方案通过调度集中系统从机调(动车调)获取机车(或动车组)的运用计划,经与实际收到的无线车次号信息匹配后,确定列车本务机机车号(或动车组车组号),从而确保调度集中系统向正确列车发送无线进路预告。该方案在不改变调度集中系统无线进路预告发送逻辑的情况下,可有效防止调度集中系统错误发送无线进路预告。

合肥南动车所车底入所作业分析及优化

随着我国高速铁路事业的不断发展,高速铁路路网规模及投入运用的动车组车底数量越来越多,各动车所运输组织任务逐渐加大。由于动车组车底运用不断增加,合肥南动车所内的运输组织作业出现困难,影响出入所效率。针对该情况,从现行站场、运用方式、人员架构等方面,对存在问题进行分析,提出车务、机务、车辆一体化运输组织的具体可行性建议,并给出近期及远期优化措施,提升了动车组车底运用效率,维护了合肥南站日常运输生产秩序,为相关动车所优化提供了参考依据。